The ever-increasing traffic and heavy wear to which pavements are exposed, aggravates the need for a rapid and efficient means for sealing the pavement to provide a long wearing surface.
Bituminous emulsions utilizing anionic emulsifiers have been widely used to seal pavements, but have been deficient in requiring a relatively long setting-time before they hardened to a useful surface. These anionic emulsions set by evaporation. Therefore, the time for setting will greatly vary depending on the temperature and humidity, as well as other environmental factors. In addition, the freshly applied emulsions are particularly susceptible to rain. If they have not hardened to a cohesive surface, a rainstorm will rapidly wash away or seriously damage the surface seal. Because of this deficiency of anionic bituminous emulsions, the prior air has sought means to shorten the setting time of such emulsions.
It is also desirable to incorporate synthetic latex polymers into bituminous emulsions in order to improve the durability of the coating which is produced and to increase the resistance of the coating to the effects of temperature.
U.S. Pat. No. 4,193,816 Ferm, issued Mar. 18, 1980, discloses quick-setting anionic bituminous emulsions in which the quick setting property is obtained by adding lime to the emulsion just prior to application to the pavement. The emulsifiers disclosed in said patent include salts of hydrocarbon sulfonic acids wherein the salt-forming cation can be an alkali metal, ammonium or substituted ammonium ion. The emulsions have a pH above 7 and can contain a synthetic rubber latex.
It is an object of the present invention to provide quick setting anionic bituminous emulsions which do not require the incorporation of an additive just prior to use. It is a further objective of the invention to provide quick setting bituminous emulsions which contain a synthetic rubber latex.